Psammechinus miliaris, the green sea urchin, is a “regular” sea urchin with a slightly flattened test and green overall color. The spines are robust, short, and closely packed. The tips of its bigger spines are violet in color. Green sea urchins can grow up to 60 mm in diameter, but typically grow up to 40 mm.

Psammechinus miliaris occurs in the North-Eastern Atlantic Ocean, North Sea, and Western Baltic Sea, mainly in shallow waters but as deep as 100 m. It is absent from the Mediterranean. Individuals are found intertidally on rocky shores under stones, boulders and seaweeds, and also subtidally in seagrass beds or on mixed coarse bottoms such as muddy sand and gravel.

About the Species

This specimen was collected in 1872 near Arendal, Norway, Eastern North Sea during the second expedition of the S.M. Avisodampfer (steamship) “Pommerania." This ship, captained by Korvettenkapitän Hoffmann, was used for botanical, zoological, fisheries, and physical marine research on two expeditions in 1871 and 1872 to the North Sea and the Baltic Sea. The specimen is part of the marine invertebrates wet collection of the ZMB.